Syphilis is a chronic classic sexually transmitted disease caused by the pale spirochete, which can invade almost every organ of the body and produce a wide variety of signs and symptoms, which are very harmful to the human body. Syphilis is definitely contagious, so what are the ways of its transmission? The first, sexual contact, which is the main route of transmission, especially untreated patients, within a year after infection is most contagious, these patients have a large number of syphilis spirochetes on the surface of the skin and mucous membrane damage, in the process of sexual contact, it is easy to pass through the skin and mucous membrane damage, even if it is very slight damage, may be transmitted to each other. Second, placental transmission, pregnant women with syphilis can transmit syphilis to their fetus through the placenta, and there is a possibility of transmission at every stage of pregnancy. Third, other rare ways are ways other than sexual contact, such as close contact with syphilis patients, breastfeeding, kissing, smoking, etc. Other than that, medical personnel may also be infected if they accidentally come into contact with specimens contaminated with syphilis spirochetes. In addition, if the blood of a patient with early syphilis is imported, it can occasionally be transmitted.